Glyset side effects: what you should know

Glyset (generic name acarbose) helps lower blood sugar spikes after meals. Most people notice that it works, but it often comes with stomach trouble. Here’s a straightforward look at the side effects you’re likely to see, which ones are rare but serious, and practical steps to cut down on problems.

Common side effects

The most common issues are gastrointestinal: gas, bloating, abdominal pain, and loose stools. Those happen because acarbose slows carbohydrate breakdown in the gut, letting more sugar reach the colon where bacteria ferment it. Symptoms are usually worst when you start the drug or after a dose increase and often get better after a few weeks.

Another common concern is mild stomach upset after certain meals—especially large or high-carbohydrate ones. If you have persistent diarrhea or belly pain that doesn’t ease, talk with your healthcare provider.

Less common but important risks

Liver enzyme elevations have been reported with acarbose. Doctors usually check liver tests before starting treatment and again if you have symptoms like dark urine, jaundice, or unusual fatigue. Stop the medicine and contact your provider if you notice those signs.

Glyset itself doesn’t usually cause low blood sugar (hypoglycemia), but if you’re also taking insulin or a sulfonylurea, your overall risk goes up. If hypoglycemia happens while on acarbose, treat it with glucose (dextrose) tablets or gel. Sucrose (table sugar) doesn’t work quickly because acarbose blocks its breakdown.

Avoid Glyset if you have inflammatory bowel disease, intestinal obstruction, or certain digestion problems. It’s also not recommended for people with diabetic ketoacidosis or significant liver disease. Always tell your prescriber about other drugs and conditions.

How to reduce and manage side effects

Start low and go slow. Typical practice is to begin with a low dose (often 25 mg with the first bite of each meal) and increase gradually every few weeks to reduce gas and diarrhea. Always take Glyset with the first bite or during the meal—taking it after eating cuts its benefit.

Smaller, more balanced meals can help. Avoiding sudden large carb loads lowers fermentation in the colon and eases gas. Over-the-counter gas relief or simethicone may help for occasional discomfort, but check with your doctor before combining treatments.

Keep an eye on symptoms: heavy or persistent diarrhea, jaundice, very dark urine, or severe stomach pain need prompt medical review. If you use insulin or sulfonylureas, monitor blood sugar more often at first and carry fast-acting glucose for emergencies.

If you’re pregnant, breastfeeding, or have chronic liver disease, ask your provider whether Glyset is right for you. Simple changes—dose adjustments, meal timing, and watching for warning signs—make Glyset tolerable for many people while still helping control post-meal blood sugar.